People who have 10 or more X-rays while sitting in the dentist's chair are far more likely to develop thyroid cancer. Researchers who made the discovery are urging dentists to restrict the use of X-rays, and to reserve them for specific clinical needs rather than as part of the routine check-up. In a study of 313 thyroid cancer patients, researchers from the Brighton and Sussex Medical School discovered that the X-rays have a cumulative effect, and that dental patients who have 10 or more have a much higher risk of developing thyroid cancer. The findings are in line with earlier studies that have established that dentists, assistants and X-ray assistants have far higher levels of thyroid cancer than the general population. (Source: Acta Oncologica, 2010; 49:447-453).